
from typing import Optional  
  
def greet(name: Optional[str] = ...):  
    if name is not None:  
        return f"Hello, {name}!"  
    else:  
        return "Hello, anonymous!"  
  

  


def test1():
    str = 'hello world'
    str2 = "hello world"
    # str3 = '''灵通'''
    
    print(str)
    print(str2)
    # print(str3)
    
    name = 'yejing'
    age = 36
    template = "My name is %s and I am %d years old." % (name,age) 
    print(template)
    template = "My name is {} and I am {} years old.".format(name, age)
    print(template)
    template = f"My name is {name} and I am {age} years old." 
    print(template)